System and method for providing access to value added services for roaming users of mobile telephones

ABSTRACT

A system for providing a roaming subscriber with access to services available in a first telephone network, when the subscriber is roaming in a second telephone network, includes a packet-switched network connecting the first telephone network with the second telephone network. Signals required for the services are transmitted between the first telephone network and the second telephone network via the packet-switched network.

FIELD OF THE INVENTION

The present invention relates to communication systems in general and tovalue added services such as voice mail in particular.

BACKGROUND OF THE INVENTION

Mobile telephone operators around the world have built an international“network of networks”. A subscriber to a particular mobile network canreceive calls when roaming in a visited mobile network. This is shown inFIG. 1, to which reference is now made, which is schematic illustrationof a prior art communication system which enables roaming. Thecommunication system comprises a home mobile network (HMN) 10 and avisited mobile network (VMN) 12 connected by a telephone infrastructure14. A mobile telephone 16 belonging to a user that has subscribed to theHMN 10 is roaming in the VMN 12. The HMN 10 comprises a mobile switchcenter (MSC) 18, a home location register (HLR) 20 and a short messageservice center (SMSC) 22. Similarly, the VMN 12 comprises an MSC 18′, avisited location register (VLR) 24 and an SMSC 22′. The HMN 10 isconnected to a voice mail system (VMS) 26.

When the mobile telephone 16 is turned on in the VMN 12, the mobiletelephone 16 registers itself in the VLR 24, which notifies the HLR 20via the telephone infrastructure 14 that the mobile telephone 16 isaccessible via the MSC 18′. When the HMN 10 receives a call for themobile telephone 16, its MSC 18 interrogates the HLR 20 and transfersthe call over the telephone infrastructure 14 to the MSC 18 of the VMN12, which transfers the call to the mobile telephone 16.

If the mobile telephone 16 is turned off or busy, the incoming call tothe MSC 18 is forwarded to the VMS 26, where a message may be recorded.In the event of a message recorded in the voice mailbox of the VMS 26for the mobile telephone 16, the VMS 26 sends a standard notification tothe SMSC 22. There are a number of problems with notifying the roamingmobile telephone 16 that a message has been recorded in the VMS 26 andwith enabling the mobile telephone 16 to retrieve the message.

One problem is that the notification is not always transferredsuccessfully to the VMN 12. For example, if the HMN 10 and VMN 12 arenot both Global System for Mobile communication (GSM) networks, then itmay not be technically possible to transfer the notification. As afurther example, the telephone infrastructure 14 may block notificationsfor technical or commercial reasons.

Another problem is that even if the mobile telephone 16 receives thenotification, the short code that the user of the mobile telephone 16dials in order to access the voice mailbox while in the HMN 10 isgenerally irrelevant in the VMN 12. For example, if the user accessesthe voice mailbox directly by dialing ‘634’ while in the HMN 10, dialing“634” while in the VMN 12 does not enable the user to access the voicemailbox. Therefore, the user must call the HMN 10 using a fullinternational number (14 digits when calling direct, 35 digits whenusing “call back” services). The user then has to dial the voice mailboxnumber and password (an additional 4 to 10 digits). It is unlikely thatthe user will complete this complex long dialing procedure correctly. Itis also unlikely that the user will try again after failing the firsttime. Another contributing factor to the failure of the long dialingprocedure is that dial tone multi-frequency (DTMF) signals aretransmitted with low quality over international telephone lines. Inprinciple, it is possible to eliminate the dialing of the voice mailboxnumber and password by using the calling line identification (CLI) ofthe mobile telephone 16 to identify which voice mailbox to use, but theCLI is also not always transmitted successfully over internationaltelephone lines.

Even when the roaming user succeeds in accessing the voice mailbox andretrieving the message, the user pays expensive international telephonerates. For this reason, most roaming users do not retrieve their voicemail messages, and many corporations even instruct their employees notto retrieve voice mail messages while roaming. This leads to a loss ofservice to the users and to a loss of income to the mobile networkoperators.

U.S. Pat. No. 5,751,792 to Chau et al. describes a system and method forproviding a message system subscriber with a roaming mailbox. Themessages in the home mailbox are transferred to a temporary roamingmailbox at a roaming node. According to Chau, the visited mobile network(VMN) must either have a dedicated voice mail system (VMS) for roamingusers or must allocate temporary mailboxes in the existing VMS of theVMN. There may not be room available in the existing VMS for allocationof temporary mailboxes. It is not clear when to delete an allocatedtemporary mailbox. Furthermore, mailboxes cost the VMN money and it maybe complicated for the VMN to be reimbursed for this cost. The user willhave to contend with an unfamiliar way to access and work with voicemail messages.

The European Telecommunications Standards Institute (ETSI) has set a newGMS standard called Customized Application of Mobile Enhanced Logic(CAMEL). The standard specifies all the components needed to let GSMnetwork operators offer the Intelligent Network (IN) services theysupply in their home country to customers that roam on foreign networks.A major disadvantage to CAMEL is that it requires an upgrade to theinstalled mobile network. This is an expensive and time-consumingprocedure. Moreover, CAMEL-compatible components are not yetcommercially available. Furthermore, non-GSM networks are not able touse CAMEL to offer IN services to roaming subscribers.

SUMMARY OF THE INVENTION

The present invention provides a novel system and method for providingaccess to value added services such as voice mail services for roamingusers of mobile telephones that overcomes the disadvantages of the priorart.

There is provided, in accordance with a preferred embodiment of thepresent invention, a system for providing a roaming subscriber withaccess to services available in a first telephone network. Thesubscriber is roaming in a second telephone network. The system includesa packet-switch network connecting the first telephone network with thesecond telephone network, wherein signals required for the services aretransmitted between the first telephone network and the second telephonenetwork via the packet-switch network.

Moreover, in accordance with a preferred embodiment of the presentinvention, the first and second telephone networks are from a groupincluding: a mobile telephone network, a fixed telephone network, aGlobal System for Mobile communications (GSM) network, a Time DivisionMultiple Access (TDMA) network, a Code Division Multiple Access (CDMA)network, an IS-41 network, and a private branch exchange (PBX).

Furthermore, in accordance with a preferred embodiment of the presentinvention, the system further includes a passive System Signaling Number7 (SS7) monitor for monitoring SS7 signals and triggering the provisionof access to at least one of the services when one of a group ofpredetermined SS7 signals has been detected.

Moreover, in accordance with a preferred embodiment of the presentinvention, the predetermined SS7 signals are Mobile Application Part(MAP) messages.

Furthermore, in accordance with a preferred embodiment of the presentinvention, the messages are from a group including: short messages andlocation updates.

Moreover, in accordance with a preferred embodiment of the presentinvention, the system further includes a first service node fortransmitting the signals between the first telephone network and thepacket-switch network, and a second service node for transmitting thesignals between the packet-switch network and the second telephonenetwork.

Furthermore, in accordance with a preferred embodiment of the presentinvention, the second service node transmits dial tone multi-frequency(DTMF) signals concurrently with the creation of a voice path connectingthe first telephone network with the second telephone network, and thefirst service node synchronizes the DTMF signals with the voice path.

Additionally, in accordance with a preferred embodiment of the presentinvention, the subscriber uses a short code dependent upon the locationof the subscriber to access the second service node.

Moreover, in accordance with a preferred embodiment of the presentinvention, the first service node instructs the second service node viathe packet-switch network to generate and send a short message.

Additionally, in accordance with a preferred embodiment of the presentinvention, the system further includes a user profile of the subscriber,the user profile comprising at least a subscriber calling lineidentification (CLI), wherein the subscriber CLI is required for accessto the services.

Moreover, in accordance with a preferred embodiment of the presentinvention, the second service node receives the subscriber CLI from DTMFsignals sent by the subscriber.

Alternatively, in accordance with a preferred embodiment of the presentinvention, the second service node receives a second CLI from the secondtelephone network end the second CLI is associated with the subscriberCLI.

Moreover, in accordance with a preferred embodiment of the presentinvention, the second service node creates a voice path connecting thesecond telephone network with be first telephone network using a secondCLI of the second service node, and the first service node replaces thesecond CLI with the subscriber CLI when accessing one of the services.

Furthermore, in accordance with a preferred embodiment of the presentinvention, the services include voice message notification.

Additionally, in accordance with a preferred embodiment of the presentinvention, the services include voice message retrieval.

There is also provided in accordance with a preferred embodiment of thepresent invention a method for providing a roaming subscriber withaccess to services available in a first telephone network. The methodincludes the steps of connecting the first telephone network to a secondtelephone network using a packet-switch network, and transmittingsignals for the services over the packet-switch network. The subscriberis roaming in the second telephone network.

Moreover, in accordance with a preferred embodiment of the presentinvention, the first and second telephone networks are from a groupincluding: a mobile telephone network, a fixed telephone network, aGlobal System for Mobile communications (GSM) network, a Time DivisionMultiple Access (TDMA) network, a Code Division Multiple Access (CDMA)network, an IS-41 network, and a private branch exchange (PBX).

Moreover, in accordance with a preferred embodiment of the presentinvention, the method further includes the steps of monitoring SS7signals and upon detection of one of a group of predetermined SS7signals, triggering the provision of access to at least one of theservices.

Furthermore, in accordance with a preferred embodiment of the presentinvention, the predetermined SS7 signals are Mobile Application Part(MAP) messages.

Additionally, in accordance with a preferred embodiment of the presentinvention, the messages are from a group including: short messages andlocation updates.

Moreover, in accordance with a preferred embodiment of the presentinvention, the method further includes the steps of transferring dialtone multi-frequency (DTMF) signals over the packet-switch network, and,concurrently with the step of transferring, creating a voice pathconnecting the first telephone network with the second telephonenetwork. The method also includes the step of synchronizing the DTMFsignals with the voice path.

Furthermore, in accordance with a preferred embodiment of the presentinvention, the method further includes the step of using a short codedependent upon the location of the subscriber to access one of theservices.

Additionally, in accordance with a preferred embodiment of the presentinvention, the method further includes the step of accessing theservices using a subscriber calling line identification (CLI) stored ina user profile of the subscriber.

Moreover, in accordance with a preferred embodiment of the presentinvention, the method further includes the step of receiving thesubscriber CLI from DTMF signals sent by the subscriber.

Furthermore, in accordance with a preferred embodiment of the presentinvention, the method further includes the step of receiving a secondCLI from the second telephone network, wherein the second CLI isassociated with the subscriber CLI.

Additionally, in accordance with a preferred embodiment of the presentinvention, the method further includes the steps of creating a voicepath connecting the second telephone network with the first telephonenetwork using a second CLI, and replacing the second CLI with thesubscriber CLI when accessing one of the services.

Moreover, in accordance with a preferred embodiment of the presentinvention, the services include voice message notification.

Furthermore, in accordance with a preferred embodiment of the presentinvention, the services include voice message retrieval.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description taken in conjunction with theappended drawings in which:

FIG. 1 is schematic illustration of a prior art communication systemwhich enables roaming;

FIG. 2 is a schematic illustration of communication system according toa preferred embodiment of the present invention;

FIG. 3 is a schematic, high-level flowchart illustration of a method forvoice mail notification, according to a preferred embodiment of thepresent invention;

FIG. 4 is a schematic, high-level flowchart illustration of a method forvoice mail message retrieval, according to a preferred embodiment of thepresent invention:

FIGS. 5A and 5B are schematic block diagram illustrations of servicenodes, according to a preferred embodiment of the present invention;

FIG. 6 is a schematic flowchart illustration of a detailed method forvoice mail notification, according to a preferred embodiment of thepresent invention;

FIG. 7 is a schematic flowchart illustration of a detailed method forvoice mail message retrieval, according to a preferred embodiment of thepresent invention; and

FIGS. 8A and 8B are schematic block diagram illustrations of servicenodes, according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention provides a novel system and method for providingaccess to and enhancements of value added services to roaming users oftelephones, by transferring certain signals over a packet-switch networkthrough service nodes connected to the telephone networks, Anon-limiting example of a packet-switch network is an Internet Protocol(IP) network Non-limiting examples of the telephone networks connectedby the packet-switch network are mobile telephone network, feedtelephone networks, Global System for Mobile communications (GSM)networks, Time Division Multiple Access (TDMA) networks, Code DivisionMultiple Access (CDMA) networks, IS-41 networks, and private branchexchanges. The term “roaming” is hereinbelow defined to include the caseof a mobile telephone user accessing services of a private branchexchange, even when the mobile telephone user is located in the homemobile network and not exclusively in a visited mobile network.

Reference is now made to FIG. 2, which is a communication systemaccording to a preferred embodiment of the present invention. Thecommunication system comprises the home mobile network (HMN) 10 and thevisited mobile network (VMN) 12 connected by the telephoneinfrastructure 14. The mobile telephone 16 belonging to a user that hassubscribed to the HMN 10 is roaming in the VMN 12. The HMN 10 comprisesthe mobile switch center (MSC) 18 and the short message service center(SMSC) 22, both of which are connected to the voice mail system (VMS)26. The HMN 10 and the VMS 26 are both connected to a service node 30.The VMN 12 comprises the MSC 18′ and the SMSC 22′. The VMN 12 isconnected to a service node 30′. The service node 30 and the servicenode 30′ are both connected to a packet-switch network, such as an IPnetwork 36. As will be described hereinbelow, the service nodes 30 and30, may include internal SMSCs 22 and 22 respectively. The followingdiscussion is equally applicable to network SMSCs and internal SMSCs.

According to another preferred embodiment of the present invention, theVMN 12 is connected to a VMS 26′, which is also connected to the servicenode 30′. The messages in the voice mailbox of the VMS 26 aretransferred via the service node 30, the IP network 36 and the servicenode 30, to a temporary mailbox of the VMS 26′. The retrievalnotification sent to the mobile telephone 16 includes a short code whichwhen dialed gives the mobile telephone 16 access to the temporarymailbox.

In an alternative preferred embodiment, the communication system alsocomprises a corporate private branch exchange (PBX) 38 having a VMS 26″,both of which are connected to a service node 30″. The service node 30″is also connected to the IP network 36.

When a new message is recorded in the voice mailbox of the VMS 26 forthe mobile telephone 16, the VMS 26 instructs the SMSC 22 to send astandard short message (SM) notification to the mobile telephone 16. Asexplained hereinabove, due to technical and commercial considerations,the standard SM notification does not always arrive at the mobiletelephone 16. The service node 30 captures the communication between theSMSC 22 and the MSC 18 using a capture device which is a passive SystemSignaling Number 7 (SS7) monitor. The service node 30 sends a messageover the IP network 36 to the service node 30′ about the new voice mailmessage. The service node 30′ instructs the SMSC 22′ to generate a shortmessage and send it to the mobile telephone 16. If the SMSC 22′ isinaccessible or too busy, then the service node 30′ uses its internalSMSC 22. If that is not possible, then the service node 30 instructs theSMSC 22 to generate the short message and send it via the telephoneinfrastructure to the mobile telephone 16. The short message includesthe short code that enables access in the VMN 12 to the service node30′. Alternatively, if the user profile indicates that the user receivesout-dial notifications, or if the service profile of the service node30, is such that it generally generates out-dial notifications, then theservice node 30′ will generate an out-dial notification to the mobiletelephone 16 with the above short code. The short message or out-dialnotification is sent to the mobile telephone 16.

The notification method is shown in the schematic, high-level flowchart130 illustration of FIG. 3, to which reference is now made. In step 100,a new voice mail message is recorded. There are three branches to thenotification method, one for short message notification, one forout-dial notification, and one for out-dial notification from thecorporate voice mail. If the VMS 26 uses short message notification,then the SMSC 22 interrogates the HLR 20 to get the roaming information(step 102). If the user is roaming, the SMSC 22 sends a short message tothe VLR 24 (step 104) and waits for confirmation. If a positiveconfirmation arrives, then the service node 30 is triggered (step 106)by the capture device. In a large network with many sites and SMSCs, thecapture device will monitor the gateway MSC (i.e. the MSC that connectsthe network to other networks) or the HLR 20. The message listened fordepends upon the device listened to, but the extracted information isthe same. The service node 30 sends a “dial short code” short message tothe mobile telephone 16 (step 108) and the internal database of theservice node 30 is updated (step 110).

If out-dial notification is used, the service node 30 gets the user ID(step 112) from the CLI of the incoming call from the VMS 26. Theservice node 30 then checks its internal database to see whether theuser is roaming (step 114). If the internal database does not indicatethat the user is roaming, then the service node 30 interrogates the HLR20 in order to locate the user (step 116). If the HLR 20 indicates thatthe user is roaming, then the service node 30 sends a “dial short code”short message to the mobile telephone 16 (step 108) and the internaldatabase of the service node 30 is updated (step 110).

In the case of a new voice mail message in the corporate VMS 26, thereis no need to check roaming, since notification is sent to the mobiletelephone 16 whether or not the user is roaming. The information in theinternal database is used to determine which service node sends theshort message for the corporate user. The service node 30″ learns of thenew message in the corporate VMS 26″ either by listening to the PBXout-dial notification or by some other integration method. If VLR 24information is missing from the internal database of the service node30, then the HLR 20 is queried for the current location of the mobiletelephone 16.

It will be appreciated that the method of FIG. 3 does not necessarilyinvolve sending a notification for each new voice mail message. Theservice profile or user profile may be configured to send a notificationaccording to a different policy, for example, for each fifth new voicemail message.

Referring back to FIG. 2, in order to retrieve the messages from thevoice mailbox, the user of the mobile telephone 16 dials the short codedisplayed in the short code notification, or presses “SEND”. This isdetected by the service node 30′ which transfers the signals such as thecalling line identification (CLI) and the dial tone multi-frequency(DTMF) signals via the (P network 36. The voice connection to the HMN 10is made either via the telephone infrastructure 14 or using voice overIP (VoIP) technology via the IP network 36. The service node 30 receivesthe transferred signals and uses them to route the call to thesubscriber's voice mailbox. If there is not enough information, then theservice node 30 connects to the common access of the VMS 26. DTMFsignals dialed by the user to access the mailbox and perform services onthe mailbox are transferred throughout the call via the IP network 36.

The voice mail message retrieval method is shown in the schematic,high-level flowchart illustration of FIG. 4, to which reference is nowmade. In step 200, the user dials the short code sent in the retrievalnotification, or presses “SEND”. If the CLI of the mobile telephone 16is available, then the service node 30′ looks up the address of the HMN10 based on the CLI of the mobile telephone (step 202). If the CLI ofthe mobile telephone is not available, the service node 30′ plays avoice prompt for the user to enter the subscriber CLI and Personalidentification Number (PIN) (step 204). The user dials the subscriberCLI and PIN and the service node 30, determines the subscriber CLI andPIN from the DTMF signals (step 206). If the PIN is invalid, the voicemall message is not retrieved. If the PIN is valid, the service node 30′looks up the address of the HMN 10 based on the subscriber CLI (step202).

It will be appreciated that if the subscriber is roaming with a rentedmobile telephone rather than with the mobile telephone that he uses inthe HMN 10, then the CLI of the rented mobile telephone will differ fromthe subscriber CLI. However, the user profile of the subscriber inservice node 30 associates the subscriber CLI with the CLI of the rentedmobile telephone.

Once the service node 30′ knows the address of the HMN 10, itcommunicates with the HMN 10 via the service node 30 over the IP network36, authenticating and authorizing the user of the mobile telephone 16(step 210). Then the service node 30′ routes the call from the mobiletelephone 16 to the HMN 10 either via the telephone infrastructure 14 orusing VOIP (step 212). It will be appreciated that this call isinitiated with the CLI of the service node 30′ and not with the CLI ofthe mobile telephone. The service node 30′ sends the CLI of the mobiletelephone over the IP network 36 to the service node 30. The servicenode 30 then uses the CLI of the mobile telephone to extract thesubscriber CLI from the user profile and route the call to the VMS 26using the subscriber CLI (step 214). The service node 30′ waits for userto hang up and then releases the voice path (step 216).

Corporate voice mail retrieval is accomplished by the same method, basedon user information stored in the internal database of service node 30.

Reference is now made to FIGS. 5A and 5B, which are schematic blockdiagram illustrations of the service nodes 30 and 30, respectively, ofFIG. 2, according to a preferred embodiment of the present invention.The service node 30 comprises a digital telephony interface (DTI) 40 anda System Signaling Number 7 (SS7) interface 42, both connected to theMSC 18 and the VMS 26. The service node 30 further comprises a CPThandler 44 and a DTMF detector 46, both connected to the DTI 40. Theservice node 30 also comprises an IP network Interface 48 connected tothe IP network 36, and a Voice Over Internet Protocol (VOIP) interface50 connected to the IP network interface 48.

The service node 30 also comprises a short message agent 52 connected tothe SMSC 22, a telephone agent 54 connected to the DTI 40, the SS7Interface 42 and the DTMF detector 46, and a personal computer (PC)agent 56.

The service node 30 further comprises a data stimulation processor (DSP)58, a dynamic call router 60, a voice function unit 62, a user profiledatabase 64, and a network management server 66. The DSP 58 is connectedto the SS7 interface 42, the short message agent 52, the telephone agent54, the VOIP interface 50 and the IP network interface 48. The dynamiccall router 60 is connected to the DSP 58, the SS7 interface 42, thetelephone agent 54 and the VOIP interface 50. The voice function unit 62is connected to the telephone agent 54 and the VOIP Interface 50. Theuser profile database 64 is connected to the PC agent 56, the voicefunction unit 62, the dynamic call router 60 and the DSP 58.

The service node 30 is identical to the service node 30 and itscomponents have the same numbers as the components of the service node30, with the addition of a tag (′) in order to differentiate between theservice nodes 30 and 30′.

Reference is now made additionally to FIG. 6, which is a schematicflowchart illustration of the notification operation of the servicenodes 30 and 30′. In step 400, a new voice mail message is recorded inthe VMS 26. The VMS 26 instructs the SMSC 22 to send a short message tothe mobile telephone 16 (step 402). The SS7 interface 42 captures thecommunication between the SMSC 22 and the MSC 18, and notifies the DSP58 that a new voice mail message has been recorded and, of the currentroaming location of the mobile telephone 16 (step 404). The DSP 58generates a notification for retrieval of the voice mail message (step406) and sends it via the IP network interface 48 over the IP network 36to the service node 30′ (step 408).

The IP network interface 48′ receives the retrieval notification fromthe IP network 36 and passes it on to the DSP 58′ (step 410). The DSP58′ instructs the short message agent 52′ to prepare a short messagebased on the retrieval notification (step 412). The short message agent52′ sends the short message to the SMSC 22′, which passes it on to themobile telephone 16 (step 414).

At this point, the user has been notified that there is a new voice mailmessage and has been instructed how to retrieve it. The user mayretrieve the message immediately upon receipt of the notification, ormay retrieve the message later. Furthermore, the user may try toretrieve voice mail messages even without receiving a retrievalnotification, by dialing the short code or pressing “SEND” for a savedshort code message.

Reference is now made additionally to FIG. 7, which is a schematicflowchart illustration of the retrieval operation of the service nodes30 and 30′. The user presses “SEND” in order to retrieve the voice mailmessage, thereby sending also the CLI via the SS7 interface 42′ (step300). The DSP 58′ performs authentication and authorization of the CLIvia the IP network 36 (step 302). This involves sending the CLI via theIP network interface 48′ over the IP network 36 to the IP networkinterface 48 and to the DSP 58, which checks the user profiles database64 for authentication and authorization. The DSP 58 then sends aconfirmation back to the DSP 58′ over the IP network 35.

In the event that the CLI is not transmitted or successfully received,the service node 30′ opens an interactive Voice Response (IVR) sessionwith the user to ask for the CLI and PIN in order to authenticate,authorize and retrieve the user profile.

Once the CLI has been authenticated and the voice mail message retrievalauthorized, the DSP 58′ instructs the telephone agent 54′ to pick up(step 304). The telephone agent 54′ instructs the DTI 40′ to pick up(step 306). Concurrently with steps 304 and 306, the DSP 58′ instructsthe dynamic call router 60′ to contact the HMN 10 to create a voice path(step 308). The voice path may use the existing telephone infrastructure14, in which case the dynamic call router 60′ contacts the HMN 10 viathe telephone agent 54, the DTI 40′ and the SS7 interface 42′, and theMSC 18′ and MSC 18. Alternatively, the voice path may use the IP network36, in which case the dynamic call router 60′ contacts the HMN 10 viathe VOIP interface 50′, the IP network interface 48′, the IP networkinterface 48, and the VOIP interface 50.

The request for voice contact arrives at the DSP 58 either via the DTI40 or via the VOIP Interface 50 (step 310). The DSP 58 extracts the CLIor mailbox address and password belonging to the mobile telephone 16from the user profiles database 64 (step 312). Using the extractedinformation, the DSP 58 then contacts the VMS 26 via the telephone agent54, thereby completing the voice path from the mobile telephone 16 tothe VMS 26 (step 314).

The user listens to the voice mall messages over the voice path andperforms additional voice mail functions such as reply, save, forward,etc. (step 316). The user operates these functions by dialing DTMFsignals. According to a preferred embodiment of the present invention,the DTMF signals are captured by the service node 30′, transferred overthe IP network 36, and regenerated by the service node 30. When the userhangs up, the voice path is released (step 318).

Reference is now made to FIGS. 8A and 8B, which are two alternateschematic block diagram illustrations of a service node, FIG. 8A showshow the components of the service node 30 could be arranged in order toform a distributed service node connected by a local area network (LAN)70, according to a preferred embodiment of the present invention. Theservice node 30 comprises a network messaging unit 72, a network agentsunit 74, a network application server 76, and the network managementserver 66. The network management server 66 comprises a maintenance unit78, an administration unit 80, a network management unit 82, a servicemanagement unit 84 and a service creation tool 86.

The maintenance unit 78 performs ongoing maintenance of the system andnetwork, including monitoring, statistics, alarms reporting andhandling, etc. Display and monitoring functions may have a graphicaluser interface. A standard network management unit is used asinfrastructure. The administration unit 80 manages the definition andupdate of the user profiles database 64, and produces billing reports ofeach user transaction message or call. The network management unit 82maintains and updates the global network topology of service nodes andtheir profiles, as well as dealing with network security issues. Theservice management unit 84 controls the activation and deactivation ofnew services and the modification of service definitions. The servicecreation tool 86 is a software package for modifying the call flow ofservices.

FIG. 8B shows an alternate arrangement of the components of the servicenode 30, according to a preferred embodiment of the present invention.The service node 30 comprises the SS7 interface 42, a capture device 90,a database 92, an application unit 94, a voice node 96 and the networkmanagement server 66. The service node 30 may also include the SMSC 22.The application unit 94 contains the logic of the service node 30 andcontrols its operation. The voice node 96 is used to connect the servicenode 30 to voice lines.

In operation, the capture device 90 monitors and filters the output of avoice mail system connected to the service node 30. When the outputcontains a message waiting indication, the application unit 94 transfersthe short message generated by the SMSC 22 via an IP network to theapplication unit 94′ of another service node 30′. The application unit94′ transfers the short message to the SMSC 22′ of the service node 30′,and the SMSC 22′ sends the short message via the mobile networkconnected to the service node 30 to a roaming mobile telephone.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to voice mail services, rather it is applicableto all value added services whose signals or data can be transferredover a packet-switch network through a service node connected to atelephone network Examples of such value added services include, but arenot limited to:

a) e-mail calls, in which users receive e-mall as a call to the mobiletelephone even while roaming;

b) wireless access to corporate intranets and other data networks;

c) voice-based information and e-commerce services tailored to travelersin accordance with their home and visited countries and languages;

d) home dialing services while roaming; and

e) fax services, using a specific cellular number as the fax gateway.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed herein above, rather the scope of the invention is defined bythe claims that follow.

1. A system for providing a roaming subscriber with access to servicesavailable in a first telephone network via a voice connection, saidsubscriber roaming in a second telephone network, the system comprising:a first service node for association with said first mobile telephonenetwork, a second service node for association with said second mobiletelephone network, a packet-switch network for connecting said firstservice node with said second service node, said first and said secondservice nodes being configured to establish a signaling connection fromsaid roaming mobile subscriber to a requested one of said services insaid first mobile telephone network and to exchange signals required forsaid services between said first mobile network and said secondtelephone network via said packet switch network thereby to support saidsubstantially seamless access, said signals comprising at least asubscriber identification signal to be transferred from said firsttelephone network to said second telephone network via saidpacket-switch network for reassociation with said voice connectionwhilst said voice connection is live.
 2. A system according to claim 1,wherein said first telephone network is one of a group including: amobile telephone network, a fixed telephone network, a Global System forMobile communications (GSM) network, a Time Divisions Multiple Access(TDMA) network, a Code Division Multiple Access (CDMA) network, an IS-41network, and a private branch exchange (PBX).
 3. A system according toclaim 1, wherein said second telephone network is one of a groupincluding: a mobile telephone network, a fixed telephone network, aGlobal System for Mobile communications (GSM) network, a Time DivisionMultiple Access (TDMA) network, a Code Division Multiple Access (CDMA)network, an IS-41 network, and a private branch exchange (PBX).
 4. Asystem according to claim 1, further comprising a passive SystemSignaling Number 7 (SS7) monitor for monitoring SS7 signals andtriggering the provision of access to at least one of said services whenone of a group of predetermined SS7 signals has been detected.
 5. Asystem according to claim 4, wherein said predetermined SS7 signals areMobile Application Part (MAP) messages.
 6. A system according to claim5, wherein said messages are from a group including: short messages andlocation updates.
 7. A system according to claim 1, wherein: said firstservice node is configured for transmitting said signals between saidfirst telephone network and said packet-switch network; and said secondservice node is configured for transmitting said signals between saidpacket-switch network and said second telephone network.
 8. A systemaccording to claim 7, wherein said second service node transmits dialtone multi-frequency (DTMF) signals substantially concurrently with thecreation of a voice path connecting said first telephone network withsaid second telephone network, and said first service node synchronizessaid DTMF signals with said voice path.
 9. A system according to claim7, wherein said subscriber uses a short code dependent upon the locationof said subscriber to access said second service node.
 10. A systemaccording to claim 7, wherein said first service node instructs saidsecond service node via said packet-switch network to generate and senda short message.
 11. A system according to claim 7, further comprising:a user profile of said subscriber, said user profile comprising at leasta subscriber calling line identification (CLI), wherein said subscriberCLI is required for access to said services.
 12. A system according toclaim 11, wherein said second service node receives said subscriber CLIfrom DTMF signals sent by said subscriber.
 13. A system according toclaim 11, wherein said second service node receives a second CLI fromsaid second telephone network and said second CLI is associated withsaid subscriber CLI.
 14. A system according to claim 11, wherein saidsecond service node creates a voice path connecting said secondtelephone network with said first telephone network using a second CLIof said second service node, and wherein said first service nodereplaces with second CLI with said subscriber CLI when accessing one ofsaid services.
 15. A system according to claim 1, wherein said servicesinclude voice message notification.
 16. A system according to claim 1,wherein said services include voice message retrieval.
 17. A systemaccording to claim 14, wherein said subscriber is enabled to use a shortcode dependent on the location of said subscriber to access said secondservice node.
 18. A system according to claim 14, wherein said firstservice node is operable to instruct said second service node via saidpacket-switch network to generate and send a short message.
 19. Thesystem of claim 1, wherein said first mobile telephone network comprisesany one of a group comprising a global system for mobile communications(GSM) network, a time division multiple access (TDMA) network, a codedivision multiple access (CDMA) network, an IS-41 network and a privatebranch exchange (PBX), and said second mobile telephone networkcomprises any other of said group.
 20. The system of claim 1, wherein:said first mobile telephone network comprises any one of a groupcomprising a global system for mobile communications (GSM) network, atime division multiple access (TDMA) network, a code division multipleaccess (CDMA) network, an IS-41 network and a private branch exchange(PBX), said second mobile telephone network comprises any one of saidgroup, but either one of said first mobile telephone network and saidsecond mobile telephone network is not a GSM network.
 21. A method forproviding a roaming subscriber at a remote telephone network with accessto services available in a first telephone network, the methodcomprising the steps of: attaching a first node to said first telephonenetwork, wherein a second node is connected to said remote telephonenetwork, and making a live voice connection between said roamingsubscriber and a requested one of said services located in said firsttelephone network, and a signaling connection between said first andsaid second node using a packet-switch network, thereby to supporttransfer of a subscriber identifying signal between said roamingsubscriber and said requested service via said packet-switch network forreassociation with said live voice connection to said services, therebyto render said at least one of said services available with voiceoperation to said roaming subscriber.
 22. A method according to claim21, wherein said first telephone network is one of a group including: amobile telephone network, a fixed telephone network, a Global System forMobile communications (GSM) network, a Time Division Multiple Access(TDMA) network, a Code Division Multiple Access (CDMA) network, an IS-41network, and a private branch exchange (PBX).
 23. A method according toclaim 21, wherein said second telephone network is one of a groupincluding: a mobile telephone network, a fixed telephone network, aGlobal System for Mobile communications (GSM) network, a Time DivisionMultiple Access (TDMA) network, a Code Division Multiple Access (CDMA)network, an IS-41 network, and a private branch exchange (PBX).
 24. Amethod according to claim 21, further comprising the steps of:monitoring SS7 signals; and upon detection of one of a group ofpredetermined SS7 signals, triggering the provision of access to atleast one of said services.
 25. A method according to claim 24, whereinsaid predetermined SS7 signals are Mobile Application Part (MAP)messages.
 26. A method according to claim 25, wherein said messages arefrom a group including: short messages and location updates.
 27. Amethod according to claim 21, further comprising the steps of:transferring dial tone multi-frequency (DTMF) signals over saidpacket-switch network; substantially concurrently with said step oftransferring, creating a voice path connecting said first telephonenetwork with said second telephone network; and synchronizing said DTMFsignals with said voice path.
 28. A method according to claim 21,further comprising the step of: using a short code dependent upon thelocation of said subscriber to access one of said services.
 29. A methodaccording to claim 21, further comprising the step of: accessing saidservices using a subscriber calling line identification (CLI) stored ina user profile of said subscriber.
 30. A method according to claim 29;further comprising the step of receiving said subscriber CLI from DTMFsignals sent by said subscriber.
 31. A method according to claim 29,further comprising the step of receiving a second CLI from said secondtelephone network, wherein said second CLI is associated with saidsubscriber CLI.
 32. A method according to claim 29, further comprisingthe steps of: creating a voice path connecting said second telephonenetwork with said first telephone network using a second CLI; andreplacing said second CLI with said subscriber CLI when accessing one ofsaid services.
 33. A method according to claim 21, wherein said servicesinclude voice message notification.
 34. A method according to claim 21,wherein said services include voice message retrieval.
 35. The method ofclaim 21, wherein said first mobile telephone network comprises any oneof a group comprising a global system for mobile communications (GSM)network, a time division multiple access (TDMA) network, a code divisionmultiple access (CDMA) network, an IS-41 network and a private branchexchange (PBX), and said second mobile telephone network comprises anyother of said group.